Composite planetary roller speed reducer without backlash transmission

Abstract

The invention discloses a backlash-free transmission compound planetary roller speed reducer which comprises a sun roller, a planetary roller, a fixed outer ring, an output outer ring, an input side planet carrier, an output side planet carrier, a positioning column, a deep groove ball bearing and a needle bearing. The sun roller is a power input structure of the compound planetary roller speed reducer, and power output is achieved through the output outer ring. The phase of the planetary roller is determined by the input side planet carrier and the output side planet carrier; the axial positions of the input side planet carrier and the output side planet carrier are determined through a positioning column; the positioning column does not move relative to the input side planet carrier and the output side planet carrier and is fixed by a bolt; the needle bearing is installed on the output side of the sun roller and aims at balancing the pressure of the output outer ring on the output side section of the planetary roller, preventing the planetary roller from being bent, counteracting the shearing force of different shaft diameter transition parts of the planetary roller and improving the frictional contact of the compound planetary roller speed reducer at the same time.

Description

Technical Field

[0001] The present invention relates to a joint reducer for an embodied intelligent robot, which is used for high-precision transmission, stable and smooth operation, and high-precision control, and belongs to the field of precision transmission. Background Art

[0002] The market prospect of embodied intelligent robots is broad and the development momentum is strong. As the core component of the robot joint, the performance of the reducer determines the operating state of the whole robot. For traditional industrial robots, RV reducers are the most widely used to bear large loads and are usually used in proximal joints; harmonic reducers have also been well developed, and their characteristics of smooth operation and high precision make them widely used in distal joints; planetary reducers are rarely used in industrial robots due to problems such as small torque density and relatively low precision. However, for embodied intelligent robots, RV reducers and harmonic reducers have high rigidity and mechanical impedance, and embodied intelligent robots require the reducer to be better coupled with the robot joint design and adapt to changing environments, so traditional RV reducers and harmonic reducers will not meet the requirements of new scenarios; on the contrary, planetary reducers, with their simple structure and flexible transmission method, have become the best solution for embodied intelligent robots. However, the shortcomings of planetary reducers are still prominent, specifically: 1) Nonlinear factors such as backlash and meshing stiffness of planetary reducers reduce the transmission accuracy and control accuracy of the reducer; 2) The gear transmission form of planetary reducers is extremely prone to failure when facing impact loads, and the reliability is low; 3) The reduction ratio of a single-stage planetary reducer is small and the torque density is low, and the multi-stage planetary reducer has a large volume and low efficiency. Therefore, developing a planetary reducer with a compact structure, impact resistance, and fast response is crucial for promoting the development of embodied intelligent robots. Summary of the Invention

[0003] Aiming at the problems of low transmission accuracy and control accuracy, difficult-to-guarantee reliability, and difficulty in achieving both torque density and efficiency of current planetary reducers, the present invention proposes a new type of composite planetary roller reducer with backlash-free transmission that can be applied to multiple scenarios. This reducer has a compact structure and a large range of reduction ratio changes, overcomes the influence of backlash of gear transmission on transmission accuracy, control effect, and reliability, and can meet different application scenarios with high precision and high dynamics.

[0004] The present invention adopts the following technical solutions:

[0005] A compound planetary roller reducer with backlash-free transmission is a new type of compound planetary roller reducer with backlash-free transmission, including a sun roller, planetary rollers, a fixed outer ring, an output outer ring, an input-side planetary carrier, an output-side planetary carrier, positioning columns, deep groove ball bearings and needle bearings; the sun roller is the power input structure of the compound planetary roller reducer, and realizes the increase and transmission of torque through the friction with 5 planetary rollers, and finally the output outer ring realizes the output of power; the best configuration attribute of the planetary roller is hollow, so as to improve the elastic deformation ability of the planetary roller; the phases of the 5 planetary rollers are determined by the input-side planetary carrier and the output-side planetary carrier; the axial positions of the input-side planetary carrier and the output-side planetary carrier are determined by 5 positioning columns; the positioning columns have no relative movement with the input-side planetary carrier and the output-side planetary carrier and are fixed by bolts; the needle bearings are installed on the output side of the sun roller, aiming to balance the pressure of the output outer ring on the output-side section of the planetary roller, prevent the bending of the planetary roller, offset the shear force of the transition part of the different shaft diameters of the planetary roller, and at the same time improve the friction contact of the compound planetary roller reducer; the rotating components such as the sun roller, planetary rollers, input-side planetary carrier, output-side planetary carrier, and output outer ring are provided with radial support by deep groove ball bearings and ensure coaxial rotation.

[0006] As a further optimization of this technical solution, a precision friction drive system with a compact structure and toothless transmission. The drive system abandons the traditional planetary gear drive, and realizes the backlash-free drive effect by replacing the gears for transmitting power with friction columns, improving the accuracy of the drive system; the sun roller of the drive system inputs torque, drives the planetary rollers to rotate through friction, and the planetary rollers drive the output outer ring to output torque through friction, and the shapes and sizes of the 5 sun rollers are the same.

[0007] As a further optimization of this technical solution, a compound planetary drive structure composed of 1 sun roller, 5 planetary rollers with different shaft diameters in two sections, a fixed outer ring and an output outer ring can select the output of the planetary carrier and the output of the output outer ring according to the reduction ratio requirements.

[0008] As a further optimization of this technical solution, a drive form for coping with high-dynamic scenarios. The drive method transmits torque through friction, avoiding failure problems such as tooth pitting, wear and tooth breakage of gear drives in high-dynamic scenarios. When facing overload, the drive form changes from pure rolling to sliding, protecting the mechanical components of the system and improving the reliability of the mechanical system.

[0009] As a further optimization of this technical solution, a compound planetary drive system that can achieve a large reduction ratio change range. In the system, controlling the two shaft diameters of the planetary rollers can realize the change of the system reduction ratio from 1:1 to 1000:1, and the reduction ratio can be flexibly adjusted and freely customized, with a more convenient development process and a simpler solution.

[0010] As a further optimization of this technical solution, a pure-rolling compound planetary transmission reducer, in which the moving parts of the reducer are driven by frictional traction, and its movement process is a pure-rolling movement without relative sliding, reducing the power loss caused by sliding friction of the reducer and improving the transmission efficiency.

[0011] As a further optimization of this technical solution, a compound planetary roller reducer with precise control, which has a constant stiffness, no nonlinear backlash, low loss, high transparency, and has a better control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the transmission principle of a compound planetary roller reducer with backlash-free transmission.

[0013] Figure 2 It is a schematic structural diagram of a compound planetary roller reducer with backlash-free transmission.

[0014] Figure 3 It is a sectional view of a compound planetary roller reducer with backlash-free transmission.

[0015] Figure 4 It is an external view of a compound planetary roller reducer with backlash-free transmission.

[0016] Markings in the figure: 1. Output outer ring; 2. Output-side planetary roller bearing; 3. Output-side sun roller bearing; 4. Needle bearing; 5. Output-side planetary carrier; 6. Output-side planetary carrier bearing; 7. Output outer ring bearing; 8. Fixed outer ring; 9. Input-side planetary carrier bearing; 10. Input-side planetary roller bearing; 11. Planetary roller; 12. Sun roller; 13. Input-side sun roller bearing; 14. Input-side planetary carrier; 15. Positioning column. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] As Figures 1 to 4 shown, a compound planetary roller reducer with backlash-free transmission of the present invention includes a sun roller, a planetary roller, a fixed outer ring and an output outer ring, a planetary carrier for restricting the position of the planetary roller, a positioning column for restricting the axial distance of the planetary carrier, and deep groove ball bearings and needle bearings of standard part models.

[0019] Before processing the compound planetary roller reducer, it is necessary to accurately calculate the deformation amounts of the sun roller, the planetary roller, the fixed outer ring and the output outer ring according to the value of the maximum output torque of the expected reducer, reasonably set the tolerances of the parts according to the deformation amounts, observe the dimensions of the deformed parts in real time during the processing and control them within a reasonable tolerance range, and complete the assembly of the compound planetary roller reducer by controlling the temperature difference during assembly.

[0020] The power input of the composite planetary roller reducer is borne by the sun roller 12. The axial position of the sun roller 12 is determined by the needle roller bearing 4 and the input-side sun roller bearing 13. The spatial positions of the needle roller bearing 4 and the input-side sun roller bearing 13 are determined by the input-side planet carrier 14 and the output-side planet carrier 5. The output-side planet carrier 5 and the input-side planet carrier 14 are determined by 5 positioning columns 15 therebetween, and the output-side planet carrier 5 and the input-side planet carrier 14 are coupled with the positioning columns 15 by bolts. The needle roller bearing 4 provides support for the output-side planetary rollers 11. The positions and connection relationships of the above components form the core transmission system of the composite planetary roller reducer; the fixed outer ring provides a supporting force for the input-side planetary rollers and the sun roller, ensuring the stable and smooth movement of the core transmission system, and is fixed during the operation of the composite planetary roller reducer. The output outer ring is the output end of the composite planetary roller reducer, used to externally connect the external equipment of the composite planetary roller reducer.

[0021] The sun roller of the composite planetary roller reducer can be designed to be hollow for connecting the output shaft of an external motor. The output shaft of the motor can be coupled with the sun roller, and the motor housing can be integrally designed with the fixed outer ring, so as to have the advantages of being more compact and having a higher degree of integration in a robot, and reducing the frictional losses caused by redundant connection methods, thereby improving the transmission efficiency.

[0022] The sun roller and the planetary rollers are designed with transition zones at different shaft diameters, which improves the strength of the rollers. Moreover, there is a gap in the transition zone between the sun roller and the planetary rollers, avoiding the friction or motion interference of the relative motion between the sun roller and the planetary rollers, and improving the efficiency of the composite planetary friction drive.

[0023] The sun roller can be designed in two sections and processed separately. During use, the two center rings with different shaft diameters are spliced by means of interference fit or other mechanical connection methods to achieve co-angular velocity rotation. There are two advantages in doing so. One is to reduce the processing difficulty of the sun roller, and the other is to improve the versatility of the sun roller. Different shaft diameters of the two sections of the sun roller can be matched to achieve different reduction ratios, which is beneficial to shortening the processing cycle and reducing the processing cost; similarly, the planetary rollers can also adopt the same structure as the sun roller, and the parts with different shaft diameters are processed separately. During use, according to the requirements of the reduction ratio and the geometric dimensions of the fixed outer ring, the output outer ring and the sun roller, the appropriate planetary rollers are selected for splicing.

[0024] The reduction ratio of the composite planetary roller reducer is determined by the diameter of the input-side sun roller, the diameter of the fixed outer ring, and the diameter of the output outer ring. Therefore, by controlling the radius ratio of the three, precise control of the reduction ratio of the reducer can be achieved, and the reduction ratio range can reach 1:1000.

[0025] The described compound planetary roller reducer is based on the traction principle, adopts a compound planetary structure, provides the traction of the system through the radial deformation of the friction contact components, realizes stable operation. When the reducer operates normally, there is no relative sliding, it has a constant stiffness, high efficiency, is easy to reverse drive, achieves tooth-free transmission in theory, and has high precision.

[0026] The working principle of a tooth-free transmission compliant planetary roller reducer of the present invention is as follows:

[0027] The sun roller 12 and the planetary roller 11 are in frictional transmission, wherein the sun roller 12 includes two sections, a d s1 section and a d s2 section; the planetary roller 11 includes two sections, a d p1 section and a d p2 section; a transition zone is designed between the d s1 section and the d s2 section of the sun roller 12 and the d p1 section and the d p2 section of the planetary roller 11; during operation, the d s1 section of the sun roller 12 meshes with the d p1 section of the planetary roller 11, and the inner wall of the fixed outer ring presses against the d p1 section of the planetary roller 11 to generate greater traction; the d p2 section of the sun roller 12 is assembled with the needle roller bearing 4 and supports the d p2 section of the planetary roller 11, and the output outer ring presses against the d p2 section of the planetary roller 11 to output greater torque; the sun roller 12 is the input of the reducer, the d s1 section and the d s2 section of the sun roller 12 rotate at the same speed, the d p1 section and the d p2 section of the planetary roller 11 rotate at the same speed and rotate in the opposite direction to the rotation direction of the sun roller 12. The revolution direction of the planetary roller 11 is the same as the rotation direction of the sun roller 12, and the output-side planet carrier 5 and the input-side planet carrier 14 have the same revolution direction and speed as the planetary roller 11. The planetary roller 11 is a hollow structure and is fully dimensionally compressible along the axial direction. During the operation of the reducer, the planetary roller 11 continuously undergoes repeated radial elastic deformation; similar to the principle of the double-tooth compound planetary gear reducer to achieve speed reduction transmission by controlling the tooth number difference between the sun gear and the ring gear, the speed reduction principle of the compound planetary roller reducer is achieved by relying on the diameter d s1 of the sun roller 12, the diameter of the fixed outer ring 8, and the diameter of the output outer ring 5. The criterion is that the diameter d s1The smaller the ratio of the diameter of the output outer ring 5 to the diameter of the fixed outer ring 8, and the closer (but not equal) the diameter of the output outer ring 5 is to the diameter of the fixed outer ring 8, the greater the reduction ratio of the speed reducer.

[0028] According to the above embodiments, the robot can achieve backlash-free high-precision smooth operation and high-reliability operation of the mechanical components of the robot in a high-dynamic scenario. Based on the above technical solutions, to solve the same technical problems, even if some non-substantive changes or refinements are made to the present invention, the essence of the technical solutions adopted is still the same as that of the present invention. Therefore, it should also be within the protection scope of the present invention.

Claims

1. A compound planetary roller reducer with backlash-free transmission, characterized in that, It includes a sun roller, planetary rollers, a fixed outer ring, an output outer ring, an input-side planet carrier, an output-side planet carrier, positioning pins, deep groove ball bearings and needle bearings; the sun roller is the power input structure of the compound planetary roller reducer, and realizes the increase and transmission of torque through friction with 5 planetary rollers, and finally the output outer ring realizes the power output; the planetary rollers are of hollow structure to improve the elastic deformation ability of the planetary rollers; the phases of the 5 planetary rollers are determined by the input-side planet carrier and the output-side planet carrier; the axial positions of the input-side planet carrier and the output-side planet carrier are determined by 5 positioning pins; the positioning pins have no relative movement with the input-side planet carrier and the output-side planet carrier and are fixed by bolts; the needle bearings are installed on the output side of the sun roller to balance the pressure of the output outer ring on the output-side section of the planetary rollers, prevent the bending of the planetary rollers, offset the shear force at the transition part of the different shaft diameters of the planetary rollers, and at the same time improve the friction contact of the compound planetary roller reducer; the sun roller, planetary rollers, input-side planet carrier, output-side planet carrier and output outer ring rotating parts are provided with radial support by deep groove ball bearings and ensure coaxial rotation.

2. The compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, The sun roller of the transmission system inputs torque and drives the planetary rollers to rotate through friction.

3. The compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, A compound planetary transmission structure composed of 1 sun roller, 5 planetary rollers with double-section different shaft diameters, a fixed outer ring and an output outer ring selects the output of the planet carrier and the output of the output outer ring according to the reduction ratio requirement.

4. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, To cope with the transmission in high-dynamic scenarios, the transmission method transmits torque through friction. When facing overload, the transmission form changes from pure rolling to sliding.

5. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, By controlling the two shaft diameters of the planetary rollers, the system reduction ratio can be changed between 1:1 and 1000:

1.

6. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, Between the moving parts of the reducer, it is driven by friction traction, and its movement process is a pure rolling motion without relative sliding, reducing the power loss caused by sliding friction of the reducer and improving the transmission efficiency.

7. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, Before machining the compound planetary roller reducer, it is necessary to accurately calculate the deformation amounts of the sun roller, planetary rollers, fixed outer ring and output outer ring according to the value of the maximum output torque expected of the reducer, reasonably set the tolerances of the parts according to the deformation amounts, observe the dimensions of the deformed parts in real time during the machining process and control them within the tolerances, and complete the assembly of the compound planetary roller reducer by controlling the temperature difference during assembly.

8. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, The sun roller is designed to be hollow to connect the output shaft of the external motor. The output shaft of the motor is coupled with the sun roller, and the motor housing is integrally designed with the fixed outer ring.

9. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, The sun roller and the planetary rollers are designed with transition zones at different shaft diameters.

10. A compound planetary roller reducer with backlash-free transmission according to claim 1, characterized in that, Sun roller and planetary roller friction drive, the sun roller includes section d s1 and section d s2 ; the planetary roller includes section d p1 and section d p2 ; between section d s1 and section d s2 of the sun roller and section d p1 and section d p2 of the planetary roller, a transition zone is designed; during operation, section d s1 of the sun roller meshes with section d p1 of the planetary roller 11, and the inner wall of the fixed outer ring presses section d p1 of the planetary roller to generate greater traction; section d p2 of the sun roller is assembled with a needle roller bearing and supports section d p2 of the planetary roller, and the output outer ring presses section d p2 of the planetary roller to output greater torque; the sun roller is the input of the reducer, section d s1 and section d s2 of the sun roller rotate at the same speed, section d p1 and section d p2 of the planetary roller rotate at the same speed and revolve in the opposite direction to the rotation direction of the sun roller, and the revolution direction of the planetary roller is the same as the rotation direction of the sun roller, and the output side planet carrier and the input side planet carrier have the same revolution direction and speed as the planetary roller; the planetary roller is a hollow structure and is fully dimensionally compressible along the axial direction, and the planetary roller undergoes continuous repeated radial elastic deformation during the operation of the reducer; similar to the principle of the double-link tooth compound planetary gear reducer to achieve speed reduction transmission by controlling the tooth number difference between the sun gear and the ring gear, the speed reduction principle of the compound planetary roller reducer relies on the diameter d s1 of the sun roller, the diameter of the fixed outer ring, and the diameter of the output outer ring; the smaller the ratio of the diameter d s1 of the sun roller to the diameter of the fixed outer ring and the closer the diameter of the output outer ring is to the diameter of the fixed outer ring, the greater the reduction ratio of the compound planetary roller reducer.

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